Biomedical subjects
Publications and source records attributed to J L Hunt.
Aeromonas hydrophilia rarely infects burn wounds. Three cases of early A. hydrophilia burn wound infection, with one death, are reported. A history of extinguishing the fire with dirty water or by rolling in dirt should alert the physician to consider A. hydrophilia as a possible infection organism.
Over an 8-year period, two epidemics of methicillin-resistant Staphylococcus aureus (MRSA) occurred in a burn unit. Sources of sepsis were the burn wound and lung. Fourteen percent of the patients colonized with MRSA became bacteremic. The mean postburn day of bacteremia was 19 and the mortality rate was 5 percent. MRSA was introduced to the burn unit when a patient was transferred from another unit, on readmission of a previously infected patient, or heavy burn census when MRSA was epidemic in the hospital. Although the morbidity rate associated with MRSA infections was high, the mortality rate was low. Gram-negative sepsis has continued to be more lethal.
Pseudomonas aeruginosa continues to be a common lethal pathogen in burned patients. Active and passive immunization represents an important therapeutic adjunct. Ten patients with Pseudomonas sepsis, eight with bacteremia, were passively immunized with tetravalent hyperimmune Pseudomonas-intravenous immunoglobulin G. The dose was 500 mg/kg given on two successive days. The IgG levels rose after infusions and were maintained in the normal range throughout the septic course. Antibodies to the immunotype of each of the Pseudomonas responsible for the bacteremias were present in the hyperimmune globulin. Clinical improvement in the patients was associated with a 3- to 125-fold postinfusion increase in antibody titers. Seventy per cent of the patients survived, including six of the seven with bacteremia.
The role of cyanide (CN) in smoke inhalation injury has been the subject of investigation for many years. Prospective evaluation of serum CN, thiocyanate (the primary metabolic product of CN), and carboxyhemoglobin (COHb) in patients suspected by history of having smoke inhalation injury was performed in 144 patients. Eight of 12 patients with "lethal" CN levels (greater than 1.0 mg/L) died. All had sublethal levels of COHb. A separate group of patients who were DOA following fatal burn injuries were also studied. Lethal CN levels were found in 12 of 14 victims with lethal COHb levels and in 14 of 20 victims with sublethal COHb levels. The results show that elevated CN levels are frequent in patients with smoke inhalation and suggest that cyanide toxicity is a contributor to severe inhalation injuries. In some cases, CN was the primary measured toxicant.
The incidence of and prophylaxis against clinically important pulmonary emboli (PE) in burned patients is an often discussed problem. To study its magnitude, all patients admitted with acute burns were followed for clinical evidence of thromboembolism: 2,106 patients were evaluated (1,439 adults). No children had evidence of PE. Six adults (0.4%) sustained a PE: none died. Mean burn size was 26.8%; mean age, 35.1 years; and mean weight, 90.8 kg. Mean PBD of the PE was 16.5 days. None with PE were ICU patients and none had lower-extremity IV lines. Two patients had embolic events after discharge from the hospital. No ICU patients who died unexpectedly had a PE. Only two patients had significant risk factors; they were obese with leg burns. Three had no risk factors; normal weight and upper body burns without prolonged bed rest. The incidence of pulmonary emboli and resulting morbidity do not justify routine prophylactic heparinization of all burned patients.
Although general awareness of child abuse is increasing, abuse by burning is often unrecognized. Seventy-one consecutive children admitted with inflicted burns were studied. Mean age was 1.8 yrs and mean burn size was 13.5%. Mean length of stay was 18.9 days. Scalds (83% from tap water) were the most frequent cause of injury. An immersion pattern was present in 59%; six patients had a classic forced immersion injury. Fourteen children had nonburn trauma. Four patients died: all had tap water immersion burns. Inflicted burns are usually manifested by characteristic patterns of injury, which must be correlated with the given history. When compared with accidentally burned children, abused children were significantly younger, had longer hospital stays, and had a higher mortality. A team approach to child abuse with the addition of a specially trained group is important to insure prompt recognition, more objective appraisals, and further followup.
Despite improvements in functional rehabilitation secondary to better control of scar and contractures, aesthetic rehabilitation of the extensively burned face has remained a difficult problem. This study was undertaken to evaluate both technique and aesthetic results of early excision and split thickness autografting (STAG) of full skin thickness face burns. Twenty-five patients with full skin thickness face burns were operated on between days 4 and 14 post-burn. Thirteen patients had excision and STAG in one stage. Twelve patients had a two-stage procedure-excision and coverage with a biological dressing followed 24-72 h later by STAG. Seven of these patients had a pressure dressing in the form of a silicone face mask applied at the second stage. Early cosmetic results were encouraging in all patients. Twenty-five per cent of patients later required either contracture release or skin resurfacing. Preliminary results are encouraging and warrant evaluation by surgeons at other centres. When early excision of full skin thickness face burns is undertaken, cautious optimism as to the ultimate aesthetic result, both by the surgeon and the patient, is advisable.
During the past 2 years a multicenter study was performed comparing Biobrane (Woodroof) and frozen cadaver allograft as temporary dressings on freshly excised full-thickness burns before the application of autograft. Each biologic dressing was evaluated with respect to the other on the same patient. Seventy-one patients were evaluated. The mean burn size was 35 +/- 20% with a mean full-thickness burn of 28 +/- 20%. Mean patient age was 34 +/- 21 years. Overall survival was 82%. The mean time of wound coverage was 10.2 +/- 6.7 days. There was no significant difference in the number of dressing changes, area changed, purulence, autograft take, and final results between allograft- and Biobrane-covered sites. There were no complications following use of either Biobrane or allograft. We conclude that Biobrane is as effective as frozen human cadaver allograft for the temporary coverage of freshly excised full-thickness burn wounds before autografting.
Pancreatic pseudocysts are a frequent complication of acute and chronic pancreatitis. The management of acute surgical emergencies associated with pseudocysts is unique. In a series of 117 patients with one or more pancreatic pseudocysts, 32% required urgent operation because of a cyst-related complication. The mean day of pseudocyst diagnosis was 7.8. Thirty percent of the patients had operation on the day of admission, while 70% required operation during cyst maturation because of an increase in size of the cyst or suspected rupture or infection. Twelve patients were found to have mature cysts at operation and had internal drainage, and external drainage was used in 56%. A pancreatic fistula developed in 22% of the patients, and septic complications occurred in 27% of surviving patients. The overall mortality was 18.9%. Mortality was 18% and 19%, respectively, for patients who had operation on the day of admission or during cyst maturation.
A review of 115 patients with pancreatic pseudocysts treated surgically between 1976 and 1984 showed four patterns of presentation: pseudocyst alone, pseudocyst and acute pancreatitis, acute pancreatitis alone, or neither apparent on hospital admission. These patterns of presentation were associated with differences in the clinical course and ultimate surgical outcome of each group of patients. Emergency procedures greatly increased the morbidity and mortality of surgery for pseudocysts. A preoperative delay for pseudocyst maturation was expected to decrease the morbidity and mortality of elective pseudocyst drainage, but no benefit was found either for the series as a whole or for any subgroup. We conclude that an arbitrary preoperative delay for pseudocyst maturation (in the absence of acute pancreatitis) exposes patients to the risks of preoperative complications, increases the expense of care for pancreatic pseudocysts, and fails to improve surgical outcome.
Chondritis may occur in up to 25 percent of burned ears and commonly follows a superficial partial-thickness injury. The onset is usually insidious and often delayed. Prevention is the key, as the treatment of an established infection frequently leads to disastrous consequences. Herein, we have reviewed 136 consecutive inpatients with burns of the ear. The burned ear was managed by careful, twice daily washing with minimal debridement, frequent application of mafenide acetate, and avoidance of pressure on the affected ear. Exposed cartilage was treated in the same manner, with surgical debridement of grossly nonviable tissue followed by skin grafting as necessary. There were no cases of chondritis in the series. Recognition of the potential for chondritis in any burn of the ear underscores the need for careful wound management, even for relatively minor injuries. The extreme difficulty of prospectively identifying the ear that will become infected coupled with the risks associated with more aggressive methods of prevention make these methods unwarranted.
Patients with burns clinically appear to require considerably larger doses of vancomycin than normal to attain therapeutic serum concentrations. It has been presumed that this phenomenon is a result of increased renal elimination of this drug consequent to increased glomerular filtration rates in such patients, as has been documented with aminoglycoside antibiotics. We measured the serum clearance of vancomycin in 10 patients with burns and found this parameter to correlate closely with creatinine clearance (serum clearance = 12.5 + 0.695 creatinine clearance; r = 0.932; P less than 0.001). The slope of this relationship was similar to that reported by other investigators in patients not suffering from thermal injury. We conclude that at all levels of renal function, patients with burns clear vancomycin in a manner similar to that of other patients. Consequently, renal function can be used to select a dosing regimen for vancomycin in such patients.
It has been common practice to perform routine electrocardiographic (EKG) monitoring of electrically burned patients for the first 24 hours following injury. Is this monitoring necessary, or is it a luxury based on remote probabilities? The records of 48 consecutive patients admitted with high-voltage (greater than 1,000 volts) electrical injuries were reviewed with respect to history of a cardiac event in the field, EKG abnormalities on admission, and the presence of cardiac arrhythmias during the first postinjury day. No serious arrhythmias occurred in any patients who had a normal EKG on admission. It was concluded that routine cardiac monitoring after a high-voltage injury should be individualized based on history of loss of consciousness, documentation of an arrythmia, or an abnormal EKG.
Energy expenditures were estimated using the Curreri equation (CEE), the Harris-Benedict equations (HBEE), and a modification of the Harris-Benedict equations (MHBEE) and then were measured by indirect calorimetry (MEE) in 17 adult patients with burns covering 26% to 79% of their body surface areas. The mean CEE (3,831 kcal/day) was significantly greater, and the mean HBEE (1,813 kcal/day) was significantly less than the mean MEE (2,500 kcal/day). The mean MHBEE (2,720 kcal/day) and the mean MEE were not significantly different.
Daily caloric requirements in patients with major burns are frequently estimated using the Curreri formula (25 X body weight (kg) + 40 X % BSA burned). In nonburned patients modifications of the Harris-Benedict formulas have been used to estimate energy requirements. These equations have not been validated against measured energy expenditures in burned patients. Thirty-five patients with second- and third-degree burns covering from 10 to 75% of the body surface area underwent assessments of energy expenditures by indirect calorimetry and by the Curreri and Harris-Benedict formulas. The mean energy expenditure calculated from the Harris-Benedict formulas (BEE) underestimated the mean measured energy expenditure (MEE) by 23% (p less than 0.001), while the mean energy expenditure calculated from the Curreri formula (CEE) overestimated the mean MEE by 58% (p less than 0.001). There were significant correlations between the MEE, BEE, and CEE. In patients with burns greater than 20% of the body surface area, the correlation between MEE and BEE was higher than that found with the Curreri formula.
Burns received as a result of motor vehicle accidents (MVA's) create special problems in their care, as they are frequently severe and are often associated with other injuries. One hundred seventy-eight consecutive patients with burns sustained in an MVA were studied. The mean TBSA burn was 33.9%. The mortality was 24.7%, but the mean burn size in this fatal group was almost doubled at 63.9%. The injury most commonly associated with death was inhalation injury (in 36.3%). Thirty-six per cent of the patients sustained other injuries in addition to their burn, the most frequent of which was to the musculoskeletal system (67 injuries). Multiple trauma had little effect on mortality unless severe, but fractures especially complicated burn wound care unless surgically stabilized. Current methods of management are presented along with our approach to multiply injured burn patients.
Missile injury to the suprarenal abdominal aorta is particularly morbid. Most patients with this injury succumb before arrival in the emergency room. The reported case is unique in that the aortic injury spontaneously decompressed into the azygos vein system, allowing early hemodynamic stability. Diagnostic and therapeutic problems included the lack of evidence of azygos dilatation on the early X-ray and difficulty in achieving control of the false aneurysm and fistula. We recommend exploration of all periaortic hematomas.
Both experimental and clinical evaluation of nitroblue tetrazolium (NBT) as a method of identifying ischemic and necrotic muscle is described. Colorless NBT was reduced to a blue formazin by viable muscle but remained colorless in necrotic muscle. Muscle samples were rated for viability on a scale of 0-100% based on the relative amount of muscle sample that reduced NBT. There was good correlation between gross appearance, distribution of staining, and histologic findings in all nonviable experimental and clinical muscle specimens. All tissue that reacted with NBT proved to be viable histologically. Metabolically active or viable muscle fibers are rich in respiratory enzymes (dehydrogenases). The loss of dehydrogenase activity from ischemic or necrotic muscle can be detected by NBT reduction capacity. NBT technique identified nonviable tissue, clearly showed the even distribution of muscle damage characteristic of electric burns, was useful in defining ischemic muscle prior to obvious necrosis, and was a rapid, simple, and reliable semiquantitative test that can be used intraoperatively.